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/*
* This file has been modified for the cdrkit suite.
*
* The behaviour and appearence of the program code below can differ to a major
* extent from the version distributed by the original author(s).
*
* For details, see Changelog file distributed with the cdrkit package. If you
* received this file from another source then ask the distributing person for
* a log of modifications.
*
*/
/* @(#)cmpbytes.c 1.15 03/06/15 Copyright 1988, 1995-2003 J. Schilling */
/*
* compare data
*
* Copyright (c) 1988, 1995-2003 J. Schilling
*/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; see the file COPYING. If not, write to the Free Software
* Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <standard.h>
#include <align.h>
#include <schily.h>
#define DO8(a) a; a; a; a; a; a; a; a;
EXPORT int
cmpbytes(fromp, top, cnt)
const void *fromp;
const void *top;
int cnt;
{
register const char *from = (char *)fromp;
register const char *to = (char *)top;
register int n;
register int i;
/*
* If we change cnt to be unsigned, check for == instead of <=
*/
if ((n = cnt) <= 0)
return (cnt);
/*
* Compare byte-wise until properly aligned for a long pointer.
*/
i = sizeof (long) - 1;
while (--n >= 0 && --i >= 0 && !l2aligned(from, to)) {
if (*to++ != *from++)
goto cdiff;
}
n++;
if (n >= (int)(8 * sizeof (long))) {
if (l2aligned(from, to)) {
register const long *froml = (const long *)from;
register const long *tol = (const long *)to;
register int rem = n % (8 * sizeof (long));
n /= (8 * sizeof (long));
do {
DO8(
if (*tol++ != *froml++)
break;
);
} while (--n > 0);
if (n > 0) {
--froml;
--tol;
to = (const char *)tol;
from = (const char *)froml;
goto ldiff;
}
to = (const char *)tol;
from = (const char *)froml;
n = rem;
}
if (n >= 8) {
n -= 8;
do {
DO8(
if (*to++ != *from++)
goto cdiff;
);
} while ((n -= 8) >= 0);
n += 8;
}
if (n > 0) do {
if (*to++ != *from++)
goto cdiff;
} while (--n > 0);
return (cnt);
}
if (n > 0) do {
if (*to++ != *from++)
goto cdiff;
} while (--n > 0);
return (cnt);
ldiff:
n = sizeof (long);
do {
if (*to++ != *from++)
goto cdiff;
} while (--n > 0);
cdiff:
return (--from - (char *)fromp);
}
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